Ink-jet recording systems allow simple and cheap image formation, and are therefore used in various printing fields. One of such ink-jet recording systems is an ultraviolet radiation-curable ink-jet system in which ink-jet ink droplets are landed on a recording medium and then cured by ultraviolet irradiation to form an image. In recent years, the ultraviolet radiation-curable ink-jet system has been attracting attention for its capability to form images having high scratch resistance and adhesiveness even on a recording medium having no ink absorbability (see, for example, Patent Literatures 1 and 2).
When an actinic radiation-curable ink that undergoes temperature-dependent reversible sol-gel phase transition is recorded on a recording medium by the ultraviolet radiation-curable ink-jet system, the ink is heated at a temperature exceeding 50° C. to a liquid state and then ejected from an ink-jet head.